Frank J. Milnar, DDS

Whether utilized for the replacement of worn or cavitated enamel or dentin, or the correction of aesthetically displeasing form or color, restorative procedures are now guided by principles of minimal intervention that dictate the manner in which treatments are planned and restorative materials are selected and placed.1 Aesthetic enhancement of intrinsically stained anterior dentition—in which no other disease is present—represents a treatment situation that can be approached with minimally invasive techniques.

Intrinsic staining of the dentition manifests following naturally occurring processes (eg, aging, disease, trauma).2-4 Dentition with intrinsic stains have responded favorably to whitening treatments of varying durations with peroxide agents.2,5-8 Alternative approaches to correct the appearance of stained dentition include placement of all-ceramic veneers or full-coverage crown restorations, in addition to placement of direct composite resins.4 Bleaching teeth prior to the placement of porcelain laminate veneers has also been advocated.4-8 Based on minimally invasive techniques, air-abrasion has also been promoted in literature as a useful alternative for the removal of extrinsic stains.9

Conservative correction of stained anterior dentition would be well suited to minimally invasive techniques that first incorporate in-office, light-activated bleaching and take-home, dentist-monitored tray bleaching. Then, if insufficient to achieve the patient’s anticipated result, the next most conservative approach in the sequence protocol would be the placement of direct composite restoratives, including recently introduced flowable varieties. These flowable composite materials—with improved physical properties, handling characteristics, and aesthetics—can contribute to a clinician’s ability to more precisely and predictably place them in order to reproduce the optical properties of natural tooth structure.10

The following case demonstrates a conservative treatment sequence for the aesthetic correction of discolored anterior maxillary dentition. In-office whitening was first performed, followed up by an at-home whitening regimen and a subsequent direct resin buildup.

Case Presentation

A 27-year-old female presented with a chief complaint that teeth #8(11) and #9(21) exhibited brown stains on the facial aspects (Figure 1). She preferred conservative treatment and was not interested in indirect veneers. Following a thorough examination that included digital photographs and radiographs, a conservative aesthetic treatment plan was developed that would proceed from the least-invasive treatment option (ie, in-office and take-home, tray-based bleaching) to the next (ie, placement of direct composite) in order to ensure that the patient’s aesthetic objectives were achieved.

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Phase 1: Tooth-Whitening Procedures

An in-office, light-activated, tooth-whitening system that contains a titanium photocatalyst was used to whiten the patient’s teeth and remove the intrinsic staining (Figure 2).11 The photocatalyst enabled the use of a lower concentration (20%) of hydrogen peroxide—thereby promoting decreased patient sensitivity12—while still achieving the desired whitening effect. While professional tooth-whitening products rely on proven technologies to reduce intrinsic stain and change the inherent tooth color, it has been proposed that the use of activating agents could enhance the performance of hydrogen peroxide and natural enzymes in the whitening process.13

In this case, the photocatalyst maximized the whitening effect of the hydrogen peroxide. Additionally, the use of a pH-balanced whitening system reduced the likelihood of tooth demineralization, which further contributed to patient comfort. Significant color changes and whitening effects were noted as a result of the interaction between the bleach and light variables.14 It has been shown that the application of light significantly improves the whitening efficacy of some bleach materials.14

Additionally, the patient followed up with 5 days of an at-home tooth-whitening regimen that contained a potassium nitrate desensitizer and sodium fluoride. While the bleaching treatment did significantly whiten the patient’s dentition, areas of white spots and hypocalcification developed in the areas that were previously stained (Figure 3).

Phase 2: Direct Composite Correction of Tooth Color

Based on the success of other clinicians in placing composite restorations to correct the appearance of such dentition,15 the decision was made to place a combination of direct restoratives. The flowable was used as a base due to its greater adaptability to the cavity walls; this made the subsequent application of a microhybrid composite necessary. Using shade tabs from the composite systems and a digital spectrophotometer, the appropriate composite shades for the dentin and enamel layers were determined (Figure 4).

Three weeks after bleaching, the white spots and hypocalcifications were removed via minimal beveled preparations (Figures 5 and 6), and the teeth were readied for the composite restorations. It has been shown that bonding composites to bleached dentition three weeks after whitening produces bond strengths similar to untreated teeth.16 The preparation design was very specific to the outline and demarcation of the hypocalcification and unaesthetic areas, with the preparations completed to the depth of the hypocalcification, into sound enamel and dentin.

The teeth were etched and adhesively conditioned using a single-component adhesive. The bonding system was brushed onto the preparations using a microbrush and allowed to sit for 10 seconds (Figure 7), after which it was thinned with high air pressure and light cured for 10 seconds per tooth with an LED curing light.

Using a syringe, the A1-shaded flowable composite was carefully placed onto teeth #8 and #9 and into the micropreparations, ensuring that the material was applied uniformly across the prepared areas (Figure 8). The handling characteristics of this flowable composite—which also contained a radiopaque, prepolymerized filler—were such that it did not slump during placement, yet moved and adapted easily to the dentin walls of the preparation. It has been noted in the literature that the improved handling characteristics available from current flowable systems have expanded today’s treatment options.10 This flowable layer was light cured for 20 seconds per tooth with an LED curing light.

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Similarly, a bleached shade of the flowable composite was applied using the syringe (Figure 9). This layer was contoured with a composite placement instrument and light cured for 20 seconds per tooth with the LED curing light.

To complete the restoration, a bleached enamel-shaded composite was placed over the dentin composite on both teeth #8 and #9 (Figure 10). The composite was carefully sculpted with instrumentation to facilitate finishing and polishing and, upon completion of placement, cured for 20 seconds per tooth.

To create surface texture and tertiary anatomy, ultra-fine polishing discs and diamond burs were used (Figures 11 and 12). To impart additional micromorphological characterizations on the facial surfaces, a 30-fluted carbide bur was also utilized (Figure 13). A total depth of cure was achieved by light curing the restorations from multiple aspects for a total of 40 seconds per tooth. Cups, points, and diamond polishing paste were used to polish the restorations and create a natural, harmonious aesthetic appearance (Figures 14 and 15).

Conclusion

Principles of minimal intervention are increasingly dictating the manner in which restorative procedures are scheduled and their related materials placed as part of an elective aesthetic protocol. In this case presentation, the patient’s aesthetic expectations were achieved through a planned sequence of conservative approaches to address the discoloration of her anterior maxillary dentition. The combined use of in-office and take-home bleaching systems designed to enhance whitening efficiency and patient comfort was implemented initially to produce the desired effects. Had the bleaching process not uncovered the underlying hypocalcifications, no further restorative treatment would have been undertaken. Since unforeseen hypocalcifications were present, however, it was necessary to proceed with the placement of a flowable composite and a microhybrid composite resin in a minimally invasive manner using micropreparations in order to achieve the patient’s aesthetic goals.When conservative preparation designs are used, it behooves clinicians to consider the incorporation of flowable composites into the restorative protocol that are well suited to such indications.17,18